1. Field of the Invention
This invention relates to the field of medical testing, and, more particularly, relates to an apparatus and method for obtaining a specimen from a bodily orifice of an animal, such as a human, which, for example, may then be analyzed or cultured to determine the presence of various organisms.
2. Description of the Related Art
Obtaining and culturing an infection provides invaluable information in the form of precise microorganism identification. That information typically enables a physician to choose and administer a form of treatment, such as a particular antibiotic, closely matched to the identified microorganism and known to be effective in treating the microorganism. Without an identification of the responsible microorganism, a physician is left with little choice but to treat an infection empirically, that is, to choose an antibiotic or other treatment that has proven effective in treating the most common organisms that cause infections. But such treatments are often suboptimal.
Before an infection may be cultured, a specimen must be obtained. Because current methods for obtaining specimens, particularly sinus-related specimens, are generally difficult and often painful and require the skills of a specialist, the benefits of a culture are, in practice, not readily available to general practitioners. Thus, infections are generally treated empirically, and, as a result, patients often receive less than optimal treatment for their infections. This is particularly true for sinus infections.
One existing technique for obtaining a sinus specimen is known as an antral tap, sometimes referred to as a canine puncture and maxillary tap. This procedure is the most common technique for obtaining a sinus culture. The antral tap procedure involves placing an instrument, such as a sturdy needle (18 gauge or thicker), or a special needle or trocar, through the face of the maxillary sinus, above the canine tooth, under the lip. The bone in this area--the canine fossa--is quite thin. The instrument is placed through the mucosa bone and the underlying sinus mucosa. Special instruments have been designed to allow rapid puncture of the bone. One such instrument, resembling a small but powerful stiletto, is designated the "sino-ject."
The antral tap procedure is an extremely painful procedure, especially in the many cases when the patient has an inflamed infected sinus. Thus, the procedure often requires general anesthesia, but, at a minimum, requires local anesthesia and sedation. As is well known, both local and general anesthesia procedures carry inherent risks. Besides pain, potential complications of the antral tap include bleeding, maxillary fracture, and even orbital or eye injuries. The antral tap procedure is limited in that it can provide a sinus specimen from the maxillary sinus only.
Another form of the antral tap procedure is similar to that described above, but is performed along the floor of the nose with penetration of the lateral nasal wall below the inferior turbinate. This form of the antral tap is just as painful, and requires a special curved needle and trocar, or other sturdy instrument, for puncture of the thin bone below the inferior turbinate. This procedure often results in severe epistaxis, with possible complications including intranasal injury, such as a persistent opening with possible chronic sinusitis, intranasal scarring, injury to the nasolacrimal duct possibly leading to epiphora or chronic tearing, or some combination of these. Both forms of antral tap must be performed by a specialist.
Another existing technique for obtaining a sinus specimen is to draw the specimen from the middle meatus (between the middle turbinate and the lateral nasal wall). The middle meatus is where the maxillary sinuses drain naturally, as do the frontal and ethmoid sinuses. While simple nasal cultures have a very low correlation with those of the maxillary sinus, cultures from the middle meatus correlate 100% with maxillary sinus cultures. This technique is useful to treat cases of maxillary sinusitis, ethmoid sinusitis and frontal sinusitis.
One primary difficulty with obtaining middle meatus specimens is contamination of the culture swab when approaching the middle meatus or when removing the swab from the middle meatus. Because of the high incidence of contaminated specimens, only skilled otolaryngologists, frequently with the aid of an endoscope, can perform the procedure with a reasonable chance for success. Moreover, with existing instruments and techniques, there is a serious risk of injury to the skull base, the brain and the orbit if the procedure is not done very carefully by a specialist.
Because of the complexity of current techniques, the serious associated risks, and the high level of skill required to obtain sinus specimens, most patients presenting with sinusitis are treated empirically. However, many studies have concluded that microorganisms are rapidly developing resistance to the most effective general antibiotics. Thus, the efficacy and availability of good empiric antibiotics is decreasing. When empiric treatments fail to stop a sinus infection, a sinus culture must be obtained. Therefore, as the effectiveness of empirical antibiotics decreases, the need for sinus cultures will increase. Moreover, many argue that all sinus infections should be cultured in the first instance.
What is needed is a technique for obtaining a specimen, and particularly a sinus specimen, that can be performed with consistent success by a general practitioner, without contamination, without substantial pain, and with minimal risk of injury to the patient.